1. Field of the Disclosure
The present invention relates to a method, apparatus and program
2. Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in the background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
In ball sports such as football, it is important to know when a goal has been scored. A goal is usually counted when the whole of the ball crosses the whole of a predetermined goal line. Match officials have the job of watching the ball and judging whether or not the ball has crossed the goal line and hence whether or not a goal has been scored. Such a system, however, although well established, can be quite unreliable. If the view of the match officials is obscured, or if one of the match officials makes an error, crucial game decisions can be made incorrectly. There is therefore a desire to implement camera and/or computer based technology to determine whether or not a ball has crossed a line so as to aid the match officials in making such decisions.
One proposal for such technology involves fitting the match ball with a sensor which may be detected by a number of detection units in such a way that the position of the ball at any one time may be computed. The sensor could, for example, emit radio frequency (RF) pulses that are picked up by the detection units at periodic intervals, with the time taken for the pulse to reach each detection unit indicating the distance of the ball from that sensor. One problem with this approach, however, is that the sensor within the ball is likely to noticeably change the weight and/or balance of the ball, which is highly undesirable. Quality control is also difficult, since it is possible for the ball to be tampered with (in the case that, for example, the ball is kicked into a crowd of spectators) so as to alter the characteristics of the sensor.
Another proposal involves fitting sensors to the two goal posts, where one goal post is placed at each end of the goal line. The sensors are then configured to detect the presence of objects that appear between them (via laser technology, for example) and can thus detect the presence of objects that cross the goal line. This system is quite unreliable, however, since it is difficult to differentiate between the ball crossing the goal line and other objects crossing the goal line (such as the football players themselves). Also, the goal posts to which the sensors are attached may experience significant movement during a football match and, further, may not be fully lined up with the goal line itself, reducing the reliability and accuracy of the system.
The present invention aims to alleviate these problems.